Tucked away at the Sierra Madre Historical Preservation Society is an intriguing photo of a young woman sitting in a leafy, patchy garden. A man with folded arms stands quietly behind her as she paints.

Photographs like this made their way from West to East at the close of the 19th century, conjuring up an imagined land where roses scented the family parlor and every garden was picture-perfect. When this image reached Aunt May in snowy Minneapolis and Cousin Bob in steamy New Orleans, its meaning was hazy. Unknown to them, this was no snapshot of quiet intimacy in a country yard. It was a staged vignette of two Americans who, through art, were capturing a uniquely California scene. The couple, framed by the arc of a branch, posed closer to the building than where, in fact, the woman composed her canvas. In design and feeling, the photograph itself was a plein-air landscape.

The year was 1887 at El Molino Viejo, the Old Mill in what is now San Marino. Built in the early 1800s by mission fathers to grind the golden wheat harvested from the San Gabriel Valley, the adobe was a stucco house and a landmark of the region's Spanish heritage under assault by railroad expansion and encroaching development. Edward Mayberry, with a fortune from land and water companies, kept the mill to house workers overseeing his 350-acre farm estate. He lived on a hill just out of sight.

The lady in a hat was Elizabeth Putnam, an art teacher from Los Angeles. She was a modern woman. Art, decorating and gardening were genteel pastimes that men permitted women; painting out-of-doors was the style of the time, possible with tube paints and the portable easel invented a decade earlier. Like artists Claude Monet and Camille Pissarro picturing the fields and cliffs of Brittany, an ancient region of rural France, Putnam was immortalizing a place resonant with memories of conquistadors and rancheros. In her finished portrait of the mill, she would preserve the lost L.A. of her generation.

For all their progress, women still lived in a man's world. On hand was Putnam's husband-to-be, Gutzon Borglum. Significantly, he loomed above his girlfriend judging her work.

From a Danish Mormon family in Idaho, Borglum was an artist trained in Paris at the studio of Auguste Rodin. With the rise of modern ideas of what makes good art, the pugnacious painter and sculptor became a strident proselytizer of realist scenes from America's recent and distant past. To his fellow artists, Borglum wrote: Abandon the familiar stories of ancient Rome and Greece. Stop returning to France and England for history. Tell the tales of our conquests and heroes. Remember our majestic forests and lakes, recall the sacrifices of the Civil War, know the courage of Lincoln and the wisdom of Jefferson. If we understand and celebrate America, we can forge a national identity for the global stage.

Borglum personally made good on his demands, most famously at Mt. Rushmore in the Black Hills of South Dakota. There he and his son, Lincoln, and 400 workers carved into granite cliffs the monumental portraits of four presidents. Their profile of George Washington was dedicated July 4, 1934.

From an artful photograph in the Sierra Madre Historical Preservation Society showing a woman painting an old mill emerges the complex tale of a couple living at a time when Americans had faith in the past to inform a better future.

Sunday we celebrate the Fourth of July, struggling to explain recent calamities in our own age of treacherous change and war, distrustful of history lessons and moral certainty. Is it possible El Molino Viejo, now a museum, still holds answers for our nation?

Watters' column runs on the first Saturday of every month. Past columns: latimes.com/lostla. Comments: home@latimes.com